Which of the following is usually an indication of a chemical change?

Question

1. Change in shape.
2. increase in volume.
3. formation in bubbles.
4. change in state of matter.

Answer 1

Among the options provided, the one that is usually an indication of a chemical change is:

3. formation of bubbles.

The formation of bubbles often indicates the release of a gas, which is a common sign of a chemical reaction. The other options (change in shape, increase in volume, and change in state of matter) can occur in physical changes as well.